Can't help you with headspacing on a 625-2(haven't gotten around to owning one ,YET) , but on my 25-2 regular .45ACP would headspace on the case mouth and fire. However, without moon clips the star would not catch the rims and eject the cases, had to punch 'em with a dowel rod. My 25-2 is on my list of "Guns I wish I had never sold".